1. Field of the Invention
The present invention relates to a ratchet wrench, and more particularly to a ratchet wrench having a simplified pawl biasing device.
2. Description of the Prior Art
Various kinds of typical ratchet wrenches have been developed and used today. U.S. Pat. No. 4,063,626 to Solomon, U.S. Pat. No. 4,762,033 to Chow, U.S. Pat. No. 5,916,339 to Dumont, and U.S. Pat. No. 6,205,891 to Huang et al. disclose four of the typical ratchet wrenches and each includes a driving stud provided on one end for fastener driving purposes. The driving head may not be disposed up-side-down such that a driving direction control device is further required to be engaged into the driving head and the handle for controlling or switching the operational directions of the driving stud.
U.S. Pat. No. 6,044,731 to Hsieh, and U.S. Pat. No. 6,220,123 to Chen disclose the other typical ratchet wrenches each including a ratchet wheel having an engaging hole provided therein for receiving fasteners. However, a single pawl is disposed in a cavity formed in the driving head and engaged with the ratchet wheel for controlling or switching the operational directions of the driving head. The formation of the cavity in the driving head may greatly decrease the strength of the driving head. In addition, the engagement of the single pawl with the ratchet wheel and the driving head is weak, such that the driving torque of the driving head against the ratchet wheel may not be increased or maintained.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ratchet wrenches.
The primary objective of the present invention is to provide a ratchet wrench including a simplified pawl biasing device for effectively actuating and operating the pawl.
In accordance with one aspect of the invention, there is provided a ratchet wrench comprising a driving head including a chamber formed therein, and including an inner peripheral gear provided therein, and including an upper and a lower peripheral shoulders formed therein. A wheel is rotatably engaged in the chamber of the driving head, and includes a barrel having an engaging hole formed therein for receiving an object to be driven by the ratchet wrench, and includes an outer peripheral portion having a pair of opposite openings formed therein. The openings of the wheel each includes an end portion. The wheel includes a first end having a peripheral flange extended radially outward therefrom for engaging with the lower peripheral shoulder of the driving head and for rotatably securing the wheel to the driving head. The wheel including a second end having a peripheral fence extended upwardly from the barrel, the peripheral fence includes an outer diameter smaller than that of the barrel for forming a peripheral shoulder between the barrel and the fence, the peripheral fence of the wheel includes an outer peripheral portion having an outer peripheral groove formed therein. The wheel includes two orifices formed in the second end thereof and offset from the openings thereof. A first and a second pawls are received in the openings of the wheel respectively, and each includes an upper portion having an aperture formed therein, and each includes an outer peripheral portion having a plurality of teeth formed thereon for engaging with the inner peripheral gear of the driving head, and each includes a first end for engaging into the end portions of the openings of the wheel respectively. A first and a second spring biasing members are received in the peripheral shoulder formed between the barrel and the fence, and each includes a first end engaged into the apertures of the first and the second pawls respectively, and each includes a second end engaged into the orifices of the wheel respectively, for biasing the first ends of the first and the second pawls into the end portions of the openings of the wheel respectively, and to determine a driving direction of the driving head to the wheel. A clamping ring is engaged into the upper peripheral shoulder of the wheel, and includes a bore formed therein for receiving the peripheral fence of the wheel, and includes a peripheral rib extended into the bore thereof for engaging into the peripheral groove of the peripheral fence and for rotatably securing the wheel to the driving head.
The engagement of the two pawls in the end portions of the openings of the wheel may increase the driving torque of the driving head to the wheel. In addition, the outer peripheral teeth of of the pawls may also be engaged with the inner peripheral gear of the driving head, such that the wheel may be solidly rotated and driven by the driving head with a greatly increased driving torque.
Further objectives and advantages of the present invention will become apparent from a careful reading of a detailed description provided hereinbelow, with appropriate reference to accompanying drawings.